JPS6153691A - Display controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display control device, and in particular to a display control device that controls an ice display (CRT) in a personal computer to display M at a predetermined tilt angle at a desired position on the screen of the display. The present invention relates to a display control device that displays lines.

[Conventional technology]

Generally, when trying to display a predetermined straight line on a display screen, data corresponding to the i1', one-line pattern is sent from an external ft, B device such as a CPU, for example.
Video RAM corresponding to the display position on the screen
The data is sequentially entered into predetermined addresses in the board, and the data is sequentially read out to display a predetermined straight line/guidance at the display position i (corresponding to each dot) on the display screen corresponding to the board address. .

In this way, data corresponding to the straight line pattern is stored at a predetermined address in the video RAM corresponding to its display position.
['Quarterite rock: In order to determine such a display position, in the conventional technology, first the first elbow ♀
When moving one dot in the X direction from the starting point position, calculate the change JXj,'ΔY in the Y direction with respect to the nucleus vertical n with respect to the amount of change ΔX in the X direction, and further calculate the change in ΔY with respect to the ΔX. The ratio, ie, ΔY/ΔX, is calculated.

Then, if the value of tentative e(-1ΔY/ΔX is 0.5 or more, move one dot in the X direction and move one dot in the Y direction from the starting point position, fit) to the next display position of the linear pattern. If the value of ΔY/ΔX is 05 drops, the next display position of the linear pattern is a position that is only moved by j dots in the X direction from the starting point position but not in the Y direction.

Based on the display position determined in this way, move one dot in the X direction again, calculate ΔYi for the change in the X direction about the straight line for the amount of change ΔX, and make the same phase as before to calculate ΔY /ΔX value is 51, and the value is 0.
Y due to movement in the X direction depending on whether it is 5 or more
It is determined whether or not to move one dot in the direction f and set the next display position.

In this way, in the prior art, when determining the display position on the display, the ratio of the amount of change ΔY in the Y direction for the gland to the amount of change ΔX in the X direction, that is, ΔY/
Calculate ΔX, and depending on whether the value is 0.5 or more, move by 1 dot in the X direction and 1 dot in the Y direction at the same time.
It was decided whether or not to move the number of dots.

In other words, in the conventional technology, the amount of change in the X direction is
Since the point of change in the Y direction is calculated based on )
In such cases, a problem arises in that the straight line cannot be displayed on the display screen. The reason for this is that when determining the display position one after another to display a predetermined straight line on the f4 spray screen, when moving one dot in the X direction, two or more dots at a time in the Y direction are required. This is because it cannot be moved (in that case, it will not form a continuous line).

[The gap that the invention attempts to solve]

In view of the above-mentioned opening point, the present invention can be applied by adding a relatively simple hardware configuration, regardless of the value of the inclination angle of the straight line displayed on the 7'4 screen. This allows straight lines to be displayed on both sides of the display.

[Means for solving problems]

According to the present invention, when displaying a straight line having a predetermined inclination angle from a predetermined starting point to an end point on an f'4 spray screen, a register in which position data of the starting point and ending point on the display screen is written; Based on the position data, the amount of change ΔX in the X direction and the amount ΔY of change in the Y direction relative to the straight line displayed on the display screen are calculated, and the amounts of change ΔX and ΔY are calculated.
The output of the address calculation circuit and the change point in the X direction are recorded based on the output of the address calculation circuit and the amount of change ΔY in the Y direction. The display (rljlJ4'
111 equipment is provided.

[Effect]

According to the present invention, if il! If the inclination angle of the 1L line is a gentle inclination of 45° or less like the straight line (,) in Figure 3 (the inclination force does not matter), then the difference between the change needle ΔX in the X direction and the amount of change ΔY in the Y direction. When a relationship of ΔX≧ΔY exists between them, the output of the address meter 31 and the circuit that outputs the change point in the X direction based on the amount of change ΔX in the X direction is selected, while the inclination angle of the straight line is Straight b (h) in Figure 3
A steep slope exceeding 45° such as
When a relationship of ΔX × ΔY exists between Y and Y, the output of the address calculation circuit that calculates the change point in the X direction using the amount of change ΔY in the Y direction as a reference is selected and outputs the address signal to the video RAM. It will be sent out.

〔Example〕

Figure 831 is a circuit diagram showing the overall configuration of the display control device 1 as an example of the present invention.
The 1” I try to display on the gray screen
A::'I will refer to the register into which the position data of the start point and end point of i are entered) and name it the start and end point register.
1. The settings can be made on the user side, and the position data of the start point and end point set in this way is sent from the CPU as pit navigation information corresponding to each coordinate value, for example, to the data bus: r, -H) r-Data bus buffer 13''t is stored in register 4.

Then, 8 inputs of data to the start and end point register 14 IB,
, an address signal corresponding to the register 14 sent from the CPU through the address bus is input to the register 14 through the address buffer 11 and address decoder 12, thereby specifying that the data should be stored in the register. .

The position data of the start and end points written in the start and end point register 14 in this manner is input to the arithmetic circuit 15. Second
This shows a specific example of the part of the arithmetic circuit 15 that calculates the address corresponding to the display position. First, the position data of the start and end points is changed from the start and end point register 14.
The amount of change ΔX in the X direction of the straight line that is input to the rig output circuit 151 and displayed on the display and the corresponding Y
The amount of change ΔY in the direction is calculated.

Next, 152 is an address calculation circuit 15311S that calculates a change point in the Y direction based on the amount of change Δχ in the X direction.
1. , is an address calculation circuit in which a change point in the X direction is calculated based on the fathering amount ΔY in the Y direction.

154 is a comparison circuit that compares the amount of change ΔX in the X direction and the amount of change ΔY in the Y direction output from the amount of change calculation circuit 151.
are compared, and if ΔX≧ΔY, the output of the sign bit generating circuit 155 will be 1 due to the signal on the output side, and if ΔX minus ΔY, the output of the sign bit generating circuit 155 will be 1. The output becomes 0.

Next, the sign bit generation circuit 155 is connected to the reverse twist circuit 156.
along with the output of address calculation circuits 152 and 153
is supplied, and the output of the sign bit generation circuit is 1.
When ΔX≧ΔY and the slope of the straight line that should be drawn is 45″ or less, the address calculation circuit 152
This output is sent to the address conversion circuit 16 through the selection circuit 156, converted into an address bus number for the video RAM, and then sent to the address bus buffer 11.
and is sent to the video RAM 3 through the multi-breather 2. On the other hand, if the output of the sign bit generation circuit is 0,
In other words, the slope of the straight line to be displayed is 4
When the number exceeds 56, the output of the address calculation circuit 153 is selected and sent to the address conversion circuit 1G.

Here, the address calculation circuit 152 is an address calculation circuit that calculates the change point in the Y direction based on the amount of change Δχ in the Every time one dot moves, the ratio of the amount of change ΔY in the Y direction for the straight line to the amount of change ΔX in the X direction, that is, ΔY/Δxl, is calculated, and the value of ΔY/ΔX is 0.
．． Depending on whether the number is 5 or more, it is determined whether or not to move one dot in the Y direction when moving one dot in the X direction.

On the other hand, the address calculation circuit 153 calculates the amount of change ΔY in the Y direction.
The point of change in the X direction is 71. Pox address Ht t? : It is a circuit, and X about the straight line with respect to the amount of change ΔY in Y direction β1]
The amount of change in direction ΔXl7) Calculate the ratio, that is, ΔX/ΔY, and depending on whether the value of ΔX/ΔY is 0.5 or more, move in the X direction when moving one dot in the Y direction. It is determined whether or not to move by one dot.

In this way, Tepai Spray U! One output of the two address calculation circuits 152 and 153 is selected depending on whether the slope of the straight line displayed on the screen 11 is 45 degrees or less, and then the output is outputted to the video via the address conversion circuit 16. RΔM3
The address for (U) and the data specifying all the arbitrary line patterns are written from the output side of the arithmetic circuit 15 to the video R at a predetermined address of M3 through the r-data bus buffer 13 and the data bus. .

By sequentially reading out the gutter via the video interface 5, a predetermined linear display is made at a predetermined display position on the screen of the CRT display 6.

Note that in FIG. 2771, a path controller 17 and a timing controller 18 are provided to send timing signals to the register 14 and the arithmetic circuit 15. The multiplexer 2 also receives the address signal from the display control device 1 and the scan address generation circuit 4.
Switching is controlled by a switching signal so that the scan address signal from

When changing the display on the display screen, the address signal from the display control device 1 is input to the video RAM 3 as described above, and at other times, the scan address signal from the scan address generation circuit 4 is input to the video RAM 3. K is input. When this scan address is input, the data in the video RAM 3 is read out sequentially and a predetermined display is performed.

〔Effect of the invention〕

According to the present invention, relatively 11 YJ year hardware +1
By adding a line structure, it is possible to display a straight line with an arbitrary inclination angle from a preset starting point to an ending point on the display screen, which further enhances the usability of this push display. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of an f'4 spray control device as an embodiment of the present invention, and FIG.
FIG. 3 is a block diagram showing a specific example, and is a diagram showing straight lines having different inclination angles that are displayed on the ice play. (Explanation of symbols) 1...Disgray control device, 12...Address decoder, 14...Start/end point register, 15...Arithmetic circuit, 151...Change 3nW-output circuit, 152, 153
...Ato v″ calculation circuit・154°°°comparison circuit・
155°°°sign (in bit generation circuit, 15
6... Selection circuit, 16... Address conversion circuit, 2.
...Multiplexer, 3...Video RAM, 6...
・CRT.

Claims (1)

[Claims] 1. When displaying a straight line having a predetermined inclination angle from a predetermined starting point to an end point on a display screen, a register in which the positional data of the starting point and end point on the display screen is written, and a register based on the positional data. The amount of change ΔX in the X direction and the amount of change ΔY in the Y direction with respect to the straight line displayed on the display screen are calculated, and the amount of change ΔX in the X direction is calculated based on the comparison result between the amount of change ΔX and ΔY. The output of the address calculation circuit that calculates the change point in the Y direction as a reference and the amount of change ΔY in the Y direction
1. A display control device comprising: an arithmetic circuit that selects an output of an address calculation circuit for calculating a change point in the X direction with reference to , and the output of the arithmetic circuit is used as an address signal for a video RAM.